Yemen has shut down its major seaports after a series of airstrikes from neighboring Saudi Arabia against rebels fighting Yemen’s Western-backed government, according to various reports.

Port of Aden officials, however, have publicly denounced the claims, saying the country’s largest container gateway is still operational despite the crisis.

Industry and local reports announced all Yemeni ports had closed Thursday after Saudi and Arab allies bombed sites near the Houthi-held capital of Sanaa. Further south, Houthis and army loyalists Friday continued to battle with militias loyal to Yemen’s President Abd-Rabbu Mansour Hadi near the port city of Aden.

The port, strategically located on the gulf of the same name, is Yemen’s major cargo seaport, and the largest natural deepwater port in the region. It is also home to the Aden Container Terminal, the largest container terminal in the Republic of Yemen.

According to a Reuters report, industry and local sources have reported Aden, as well as ports in Al Mukalla, Al Mokha and Al Hudaydah, have been closed in the aftermath of the Saudi airstrikes.

“All major seaports were shut down on Thursday due to the rising conflict,” an anonymous industry source is quoted. Local sources in Yemen have confirmed the closure, Reuters said.

The reports fly in the face of statements from some port officials in Yemen, who have argued that terminals were still in operation.

“Leadership confirms that the shipping traffic at the Port of Aden is working smoothly and nothing disturbs it,” the port said in a statement Thursday. “The leadership denies news from some websites about any threats to the port and invited them to be cautious in publishing such news.”

Nevertheless, the U.S. Coast Guard has issued restrictions on certain vessels arriving at U.S. ports from a number of Yemeni gateways that “do not maintain effective anti-terrorism measures”, according to a statement.

The crisis in Yemen has heightened concerns over the country’s primary export: oil. Yemen exports about 1.4 to 1.5 million barrels of Masila crude each month, largely to China. It is far from being the biggest player in the Mid-East oil market, but the current port shutdown has heightened concerns the Yemeni crisis could stunt oil supplies from the entire region.

For years, Yemen has been seen as a proxy battleground for Sunni-dominated Saudi Arabia and Shia Iran, which is suspected of supporting the Houthi rebels. The conflict in the region came to a head this week after President Hadi fled the country by sea Wednesday as Houthi Shiite rebels and their allies moved on his last refuge in the south, captured its airport and put a bounty on the president’s head.

Although Yemen produces only a small amount of oil itself, Saudi Arabia and the Gulf Cooperation Council states are nervous of any conflict that could affect the Gulf of Aden, which sees roughly 3.8 million barrels of oil pass through its waters daily.

The unrest in the country, which some fear could turn into civil war or an even wider regional conflict, prompted a 5 percent spike in the price of Brent crude Thursday.

An analyst for Verisk Maplecroft quoted by Reuters Thursday described the oil price hike as “a bit of an overreaction” but warned that the Houthi takeover had “significant geopolitical repercussions in that it adds to Iran’s growing regional clout.”